The capacity of digital storage media like hard disks or rewritable optical disks for personal recording of video and other data grows continuously. This results in new concepts like e.g. the so-called home server, which is a central storage device with large capacity for recording any kind of data within the home. Such applications also require new ways to organize the recorded data, search for content and access specific recordings.
For this purpose data about data, often referred to as metadata, can be used. Various industry groups and standard bodies have been developing metadata standards for different purposes and, applications. In multimedia applications, metadata typically are data about audiovisual (AV) data, these AV data often being called ‘essence’. However, a Data Base Management System (DBMS) that shall be able to handle data of various data types correctly requires a definition of data types, and a method to distinguish between them.